statesync: improve e2e test outcomes (backport #6378) (#6380)

(cherry picked from commit d36a5905a6)

Co-authored-by: Sam Kleinman <garen@tychoish.com>

CHANGELOG_PENDING.md

@@ -22,4 +22,6 @@ Friendly reminder, we have a [bug bounty program](https://hackerone.com/tendermi
 
 ### IMPROVEMENTS
 
+- [statesync] \#6378 Retry requests for snapshots and add a minimum discovery time (5s) for new snapshots.
+
 ### BUG FIXES

config/config.go

@@ -761,6 +761,10 @@ func (cfg *StateSyncConfig) ValidateBasic() error {
 				return errors.New("found empty rpc_servers entry")
 			}
 		}
+		if cfg.DiscoveryTime != 0 && cfg.DiscoveryTime < 5*time.Second {
+			return errors.New("discovery time must be 0s or greater than five seconds")
+		}
+
 		if cfg.TrustPeriod <= 0 {
 			return errors.New("trusted_period is required")
 		}

statesync/reactor.go

@@ -255,11 +255,16 @@ func (r *Reactor) Sync(stateProvider StateProvider, discoveryTime time.Duration)
 	r.syncer = newSyncer(r.Logger, r.conn, r.connQuery, stateProvider, r.tempDir)
 	r.mtx.Unlock()
 
-	// Request snapshots from all currently connected peers
-	r.Logger.Debug("Requesting snapshots from known peers")
-	r.Switch.Broadcast(SnapshotChannel, mustEncodeMsg(&ssproto.SnapshotsRequest{}))
+	hook := func() {
+		r.Logger.Debug("Requesting snapshots from known peers")
+		// Request snapshots from all currently connected peers
+		r.Switch.Broadcast(SnapshotChannel, mustEncodeMsg(&ssproto.SnapshotsRequest{}))
+	}
+
+	hook()
+
+	state, commit, err := r.syncer.SyncAny(discoveryTime, hook)
 
-	state, commit, err := r.syncer.SyncAny(discoveryTime)
 	r.mtx.Lock()
 	r.syncer = nil
 	r.mtx.Unlock()

statesync/snapshots.go

@@ -173,8 +173,8 @@ func (p *snapshotPool) Ranked() []*snapshot {
 	defer p.Unlock()
 
 	candidates := make([]*snapshot, 0, len(p.snapshots))
-	for _, snapshot := range p.snapshots {
-		candidates = append(candidates, snapshot)
+	for key := range p.snapshots {
+		candidates = append(candidates, p.snapshots[key])
 	}
 
 	sort.Slice(candidates, func(i, j int) bool {

statesync/syncer.go

@@ -24,6 +24,9 @@ const (
 	chunkTimeout = 2 * time.Minute
 	// requestTimeout is the timeout before rerequesting a chunk, possibly from a different peer.
 	chunkRequestTimeout = 10 * time.Second
+	// minimumDiscoveryTime is the lowest allowable time for a
+	// SyncAny discovery time.
+	minimumDiscoveryTime = 5 * time.Second
 )
 
 var (
@@ -125,7 +128,11 @@ func (s *syncer) RemovePeer(peer p2p.Peer) {
 // SyncAny tries to sync any of the snapshots in the snapshot pool, waiting to discover further
 // snapshots if none were found and discoveryTime > 0. It returns the latest state and block commit
 // which the caller must use to bootstrap the node.
-func (s *syncer) SyncAny(discoveryTime time.Duration) (sm.State, *types.Commit, error) {
+func (s *syncer) SyncAny(discoveryTime time.Duration, retryHook func()) (sm.State, *types.Commit, error) {
+	if discoveryTime != 0 && discoveryTime < minimumDiscoveryTime {
+		discoveryTime = 5 * minimumDiscoveryTime
+	}
+
 	if discoveryTime > 0 {
 		s.logger.Info(fmt.Sprintf("Discovering snapshots for %v", discoveryTime))
 		time.Sleep(discoveryTime)
@@ -148,6 +155,7 @@ func (s *syncer) SyncAny(discoveryTime time.Duration) (sm.State, *types.Commit,
 			if discoveryTime == 0 {
 				return sm.State{}, nil, errNoSnapshots
 			}
+			retryHook()
 			s.logger.Info(fmt.Sprintf("Discovering snapshots for %v", discoveryTime))
 			time.Sleep(discoveryTime)
 			continue

statesync/syncer_test.go

@@ -186,7 +186,7 @@ func TestSyncer_SyncAny(t *testing.T) {
 		LastBlockAppHash: []byte("app_hash"),
 	}, nil)
 
-	newState, lastCommit, err := syncer.SyncAny(0)
+	newState, lastCommit, err := syncer.SyncAny(0, func() {})
 	require.NoError(t, err)
 
 	time.Sleep(50 * time.Millisecond) // wait for peers to receive requests
@@ -210,7 +210,7 @@ func TestSyncer_SyncAny(t *testing.T) {
 
 func TestSyncer_SyncAny_noSnapshots(t *testing.T) {
 	syncer, _ := setupOfferSyncer(t)
-	_, _, err := syncer.SyncAny(0)
+	_, _, err := syncer.SyncAny(0, func() {})
 	assert.Equal(t, errNoSnapshots, err)
 }
 
@@ -224,7 +224,7 @@ func TestSyncer_SyncAny_abort(t *testing.T) {
 		Snapshot: toABCI(s), AppHash: []byte("app_hash"),
 	}).Once().Return(&abci.ResponseOfferSnapshot{Result: abci.ResponseOfferSnapshot_ABORT}, nil)
 
-	_, _, err = syncer.SyncAny(0)
+	_, _, err = syncer.SyncAny(0, func() {})
 	assert.Equal(t, errAbort, err)
 	connSnapshot.AssertExpectations(t)
 }
@@ -255,7 +255,7 @@ func TestSyncer_SyncAny_reject(t *testing.T) {
 		Snapshot: toABCI(s11), AppHash: []byte("app_hash"),
 	}).Once().Return(&abci.ResponseOfferSnapshot{Result: abci.ResponseOfferSnapshot_REJECT}, nil)
 
-	_, _, err = syncer.SyncAny(0)
+	_, _, err = syncer.SyncAny(0, func() {})
 	assert.Equal(t, errNoSnapshots, err)
 	connSnapshot.AssertExpectations(t)
 }
@@ -282,7 +282,7 @@ func TestSyncer_SyncAny_reject_format(t *testing.T) {
 		Snapshot: toABCI(s11), AppHash: []byte("app_hash"),
 	}).Once().Return(&abci.ResponseOfferSnapshot{Result: abci.ResponseOfferSnapshot_ABORT}, nil)
 
-	_, _, err = syncer.SyncAny(0)
+	_, _, err = syncer.SyncAny(0, func() {})
 	assert.Equal(t, errAbort, err)
 	connSnapshot.AssertExpectations(t)
 }
@@ -320,7 +320,7 @@ func TestSyncer_SyncAny_reject_sender(t *testing.T) {
 		Snapshot: toABCI(sa), AppHash: []byte("app_hash"),
 	}).Once().Return(&abci.ResponseOfferSnapshot{Result: abci.ResponseOfferSnapshot_REJECT}, nil)
 
-	_, _, err = syncer.SyncAny(0)
+	_, _, err = syncer.SyncAny(0, func() {})
 	assert.Equal(t, errNoSnapshots, err)
 	connSnapshot.AssertExpectations(t)
 }
@@ -336,7 +336,7 @@ func TestSyncer_SyncAny_abciError(t *testing.T) {
 		Snapshot: toABCI(s), AppHash: []byte("app_hash"),
 	}).Once().Return(nil, errBoom)
 
-	_, _, err = syncer.SyncAny(0)
+	_, _, err = syncer.SyncAny(0, func() {})
 	assert.True(t, errors.Is(err, errBoom))
 	connSnapshot.AssertExpectations(t)
 }

test/e2e/app/snapshots.go

@@ -2,7 +2,6 @@
 package main
 
 import (
-	"crypto/sha256"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -88,11 +87,10 @@ func (s *SnapshotStore) Create(state *State) (abci.Snapshot, error) {
 	if err != nil {
 		return abci.Snapshot{}, err
 	}
-	hash := sha256.Sum256(bz)
 	snapshot := abci.Snapshot{
 		Height: state.Height,
 		Format: 1,
-		Hash:   hash[:],
+		Hash:   hashItems(state.Values),
 		Chunks: byteChunks(bz),
 	}
 	err = ioutil.WriteFile(filepath.Join(s.dir, fmt.Sprintf("%v.json", state.Height)), bz, 0644)
@@ -111,10 +109,9 @@ func (s *SnapshotStore) Create(state *State) (abci.Snapshot, error) {
 func (s *SnapshotStore) List() ([]*abci.Snapshot, error) {
 	s.RLock()
 	defer s.RUnlock()
-	snapshots := []*abci.Snapshot{}
-	for _, snapshot := range s.metadata {
-		s := snapshot // copy to avoid pointer to range variable
-		snapshots = append(snapshots, &s)
+	snapshots := make([]*abci.Snapshot, len(s.metadata))
+	for idx := range s.metadata {
+		snapshots[idx] = &s.metadata[idx]
 	}
 	return snapshots, nil
 }